Revert of Remove the is_loading_ field from WebContentsImpl

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 4b2a6f63eb26d047b9ec8d1958896be2eb9d8925..e8a8038cacf386ca8ea24ee2b048485a4ad061bb 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -214,7 +214,6 @@
   g_routing_id_frame_map.Get().insert(std::make_pair(
       RenderFrameHostID(GetProcess()->GetID(), routing_id_),
       this));
-  site_instance_->AddObserver(this);
 
   if (is_swapped_out) {
     rfh_state_ = STATE_SWAPPED_OUT;
@@ -263,8 +262,6 @@
   g_routing_id_frame_map.Get().erase(
       RenderFrameHostID(GetProcess()->GetID(), routing_id_));
 
-  site_instance_->RemoveObserver(this);
-
   if (delegate_ && render_frame_created_)
     delegate_->RenderFrameDeleted(this);
 
@@ -520,6 +517,7 @@
                         OnDidFailLoadWithError)
     IPC_MESSAGE_HANDLER_GENERIC(FrameHostMsg_DidCommitProvisionalLoad,
                                 OnDidCommitProvisionalLoad(msg))
+    IPC_MESSAGE_HANDLER(FrameHostMsg_DidDropNavigation, OnDidDropNavigation)
     IPC_MESSAGE_HANDLER(FrameHostMsg_UpdateState, OnUpdateState)
     IPC_MESSAGE_HANDLER(FrameHostMsg_OpenURL, OnOpenURL)
     IPC_MESSAGE_HANDLER(FrameHostMsg_DocumentOnLoadCompleted,
@@ -692,13 +690,6 @@
   return NULL;
 }
 
-void RenderFrameHostImpl::RenderProcessGone(SiteInstanceImpl* site_instance) {
-  DCHECK(site_instance == site_instance_.get());
-
-  // The render process is gone, this frame can no longer be loading.
-  ResetLoadingState();
-}
-
 bool RenderFrameHostImpl::CreateRenderFrame(int proxy_routing_id,
                                             int opener_routing_id,
                                             int parent_routing_id,
@@ -1049,6 +1040,15 @@
   // PlzNavigate
   if (IsBrowserSideNavigationEnabled())
     pending_commit_ = false;
+}
+
+void RenderFrameHostImpl::OnDidDropNavigation() {
+  // At the end of Navigate(), the FrameTreeNode's DidStartLoading is called to
+  // force the spinner to start, even if the renderer didn't yet begin the load.
+  // If it turns out that the renderer dropped the navigation, the spinner needs
+  // to be turned off.
+  frame_tree_node_->DidStopLoading();
+  navigation_handle_.reset();
 }
 
 void RenderFrameHostImpl::OnUpdateState(const PageState& state) {
@@ -1315,8 +1315,6 @@
     // We are now deleted.
     return;
   }
-
-  ResetLoadingState();
 
   // If this RFH wasn't pending deletion, then it is now swapped out.
   SetState(RenderFrameHostImpl::STATE_SWAPPED_OUT);
@@ -1703,10 +1701,23 @@
 }
 
 void RenderFrameHostImpl::OnDidStartLoading(bool to_different_document) {
-  bool was_previously_loading = frame_tree_node_->frame_tree()->IsLoading();
+  // Any main frame load to a new document should reset the load since it will
+  // replace the current page and any frames.
+  if (to_different_document && !GetParent())
+    is_loading_ = false;
+
+  // This method should never be called when the frame is loading.
+  // Unfortunately, it can happen if a history navigation happens during a
+  // BeforeUnload or Unload event.
+  // TODO(fdegans): Change this to a DCHECK after LoadEventProgress has been
+  // refactored in Blink. See crbug.com/466089
+  if (is_loading_) {
+    LOG(WARNING) << "OnDidStartLoading was called twice.";
+    return;
+  }
+
+  frame_tree_node_->DidStartLoading(to_different_document);
   is_loading_ = true;
-  frame_tree_node_->DidStartLoading(to_different_document,
-                                    was_previously_loading);
 }
 
 void RenderFrameHostImpl::OnDidStopLoading() {
@@ -1902,7 +1913,7 @@
   // Blink doesn't send throb notifications for JavaScript URLs, so it is not
   // done here either.
   if (!common_params.url.SchemeIs(url::kJavaScriptScheme))
-    OnDidStartLoading(true);
+    frame_tree_node_->DidStartLoading(true);
 }
 
 void RenderFrameHostImpl::NavigateToInterstitialURL(const GURL& data_url) {
@@ -2241,18 +2252,6 @@
   return mojo_image_downloader_;
 }
 
-void RenderFrameHostImpl::ResetLoadingState() {
-  if (is_loading()) {
-    // When pending deletion, just set the loading state to not loading.
-    // Otherwise, OnDidStopLoading will take care of that, as well as sending
-    // notification to the FrameTreeNode about the change in loading state.
-    if (rfh_state_ != STATE_DEFAULT)
-      is_loading_ = false;
-    else
-      OnDidStopLoading();
-  }
-}
-
 bool RenderFrameHostImpl::IsSameSiteInstance(
     RenderFrameHostImpl* other_render_frame_host) {
   // As a sanity check, make sure the frame belongs to the same BrowserContext.